Cantilever Protraction Device

A large percentage of people are maxillary deficient relative to their genetic potential for maxillary development. In order to achieve this full maxillary development potential, protractionary forces must be applied to the bone. According to Newton's third law of motion, for every action there is an equal and opposite reaction. Therefore, in order to apply this protractionary force on the maxilla, a device must be capable of handling the opposite reaction.

In traditional orthodontics, convenience has taken priority, and many suboptimal physiologic negative anchorage points have been attempted, including the forehead, cheekbones, chin, and neck. However, applying a negative force to sensitive regions of the body for the long periods of time required for protraction is far from ideal and even harmful in many cases. For example, negative force application on the mandible/chin (such as in U.S. Pat. No. 8,640,710) is associated with mandibular recession and temporomandibular joint stress generation. Devices using a neck brace immobilize the neck and create large amounts of heat and discomfort in the sensitive neck region. Negative force on the frontal bone or cheekbones can create deformation and recession of the bone structure over time. For example, the maxillary protraction device described in U.S. Patent Publication No. 2018/0028282 places significant loads upon the head and provides only limited head movement due to a body anchor having only a single point of articulation anchored to an immobile location on a patient's abdomen.

There is a need in the art for improved protraction devices. The present invention addresses this need.

In one aspect, the present invention relates to a cantilever protraction device comprising: a frame; a headpiece slidably connected to a headpiece rail having a curvature; and a cantilever support slidably connected to the frame, the cantilever support having an upper end attached to the headpiece rail.

In one embodiment, the frame comprises at least one upper lateral rail and at least one lower lateral rail connected by opposing side rails, the lateral rails being in parallel alignment and having equal curvatures. In one embodiment, the frame is constructed from one or more shaft sections. In one embodiment, at least a portion of the shaft sections are adjustably telescoping.

In one embodiment, the device further comprises at least one strap pad tautly suspended between the opposing side rails, the at least one strap pad comprising padding constructed from a gel or a foam. In one embodiment, the frame comprises a harness having shoulder and waist straps. In one embodiment, the harness and the at least one strap pad are configured to secure the device to a subject such that frame does not physically touch the subject or minimally touches the subject.

In one embodiment, the curvature of the lateral rails is a circular arc having an angle between about 160° and 180°. In one embodiment, the headpiece rail curvature is a circular arc having an angle between about 90° and 140°.

In one embodiment, the device further comprises a linkage arm attached to the headpiece, the linkage arm having a curvature equal to the headpiece rail. In one embodiment, the headpiece further comprises one or more attachments slidably connected to the headpiece rail and lockable to the linkage arm, the one or more attachments selected from a hook attachment, a linear gear bar attachment, and combinations thereof.

In one embodiment, the slidable connections comprise a low friction bearing. In one embodiment, the low friction bearing is constructed from a material selected from polytetrafluoroethylene (PTFE), ultra high molecular weight polyethylene (UHMWPE), and combinations thereof.

In one embodiment, the headpiece is slidable along the headpiece rail in a medial plane and configured to support flexion and extension of a subject's head. In one embodiment, the cantilever support is slidable along the frame along a transverse plane and configured to support rotation of a subject's head. In one embodiment, the attachment between the cantilever support and the headpiece rail comprises a rotatable joint permitting rotation in a coronal plane, the rotatable joint configured to support lateral flexion of a subject's head.

In another aspect, the present invention relates to an anchored protraction device, comprising: a rail having a curvature, the rail being attached to an anchor; a head brace slidably connected to the rail; and an elongate linkage arm attached to the head brace.

In one embodiment, the anchor is securable to a gurney, a bed headboard, a floor stand, and combinations thereof. In one embodiment, the device further comprises one or more attachments slidably connected to the rail and lockable to the linkage arm, the one or more attachments selected from a hook attachment, a linear gear bar attachment, and combinations thereof.

In one embodiment, the slidable connections comprise a low friction bearing. In one embodiment, the low friction bearing is constructed from a material selected from polytetrafluoroethylene (PTFE), ultra high molecular weight polyethylene (UHMWPE), and combinations thereof.

In a third aspect, the invention is a protraction device comprising a body frame and a cantilever support. The body frame is adapted to be anchored to the body of a patient. The cantilever support includes a first shaft, coupled to the body frame, and a second shaft, coupled to the first shaft. The second shaft extends in front of the face of the patient.

In a fourth aspect, the invention is a protraction system comprising a therapeutic appliance, a protraction device, and a force applicator. The therapeutic appliance is coupled to a patient. The protraction device includes a body frame and a cantilever support, coupled to the body frame by a roller bearing. The force applicator is removably coupled to the cantilever support and to the therapeutic appliance. The therapeutic appliance is anchored to at least one member selected from the group consisting of the teeth, bone, and soft tissue of the patient.

In a fifth aspect, the invention is a method of providing maxillary protraction to a patient in need thereof comprising coupling a protraction device to a therapeutic appliance. The therapeutic appliance is coupled to the patient.

In a sixth aspect, the invention is a headpiece comprising a first strap, a harness, and a second strap. The first strap is configured to encircle the back and sides of the head of a patient. The harness is removably coupled to the first strap by a plurality of fasteners. The second strap is configured to pass under the jaw of the patient and is coupled to the harness. The second strap comprises a mandible fastener. The harness does not obstruct the facial area of the patient.

In a seventh aspect, the invention is a protraction device comprising an anchor, a cantilever support, a headpiece, and a force applicator. The cantilever support includes a shaft movably coupled to the anchor. The headpiece is adjustably coupled to the shaft. The force applicator is removably coupled to the headpiece and adjustably coupled to the shaft. The anchor is configured to be secured to a supporting object.

In an eighth aspect, the invention is a protraction system comprising a therapeutic appliance and a trans-oral member. The therapeutic appliance is adapted to be coupled to at least one member selected from the group consisting of the teeth, bone, and soft tissue of a patient. The trans-oral member includes a curved member and an extra-oral vertical member. Each end of the curved member is coupled to opposing ends of the therapeutic appliance. The extra-oral vertical member extends vertically from the plane of the curved member.

The present invention provides body anchored protraction devices and off-the-head anchored protraction devices. The protraction devices direct the negative forces of protraction over a large surface area on the chest and abdomen of a patient. The protraction devices are lightweight and employ a cantilever support rod and ultra-low friction joints to enable low compression on the head with low resistance to head movements.

It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for the purpose of clarity, many other elements typically found in the art. Those of ordinary skill in the art may recognize that other elements and/or steps are desirable and/or required in implementing the present invention. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements and steps is not provided herein. The disclosure herein is directed to all such variations and modifications to such elements and methods known to those skilled in the art.

Unless defined elsewhere, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and materials are described.

As used herein, each of the following terms has the meaning associated with it in this section.

The articles “a” and “an” are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

“About” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1%, and ±0.1% from the specified value, as such variations are appropriate.

The term “supporting object” means an object having a rigid surface that is capable of physically supporting an anchored protraction device. Examples of supporting objects include walls, beds, gurneys and stands, such as floor stands.

Throughout this disclosure, various aspects of the invention can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, 6, and any whole and partial increments therebetween. This applies regardless of the breadth of the range.

The present invention provides protraction devices that are configured to direct the negative forces of maxillary protraction to the chest and abdomen and away from the sensitive regions of the head and neck of a patient. The devices spread the negative force out over a large surface area to reduce fatigue and discomfort. Wearable devices are lightweight, such as in the range of 1 to 2 lbs and below, and permit a patient's head to retain substantial freedom of motion, including rotation and nodding. Referring now to, an exemplary body anchored protraction deviceis depicted. Devicecomprises body frame, cantilever support, and headpiece.

Referring now to, body frameis described in detail. Body framecomprises one or more sections of shaftforming a perimeter. Body framecan have any suitable shape, such as a substantially quadrilateral or elliptical shape. Shaftcan be hollow or solid and can be constructed from any suitably rigid material, such as aluminum, polycarbonate, or some other lightweight metal, plastic, or composite material. In various embodiments, shaftcan have any suitable cross section, including circular, elliptical, square, and rectangular. At a top side and a bottom side, shaftforms upper railand lower rail, respectively, each connected to opposing side rails. Upper railand lower railare aligned in parallel (see) and have matching curvatures. In some embodiments, the matching curvatures can be described as a circular arc having an angle between about 160° and 180°. In some embodiments, body framecan comprise one or more additional lateral rails aligned in parallel with upper railand lower railand having matching curvatures. The one or more additional lateral rails can be connected to side rails, or to upper railor lower rail, such as by a short segment of shaft. Side railscan have one or more indentsconfigured to conform to a patient's anatomy, such as the pectoral muscles.

Body framecan be secured to a patient's body using any suitable mechanism. For example, in some embodiments body framefurther comprises strap padssuspended between side rails. Strap padscan be constructed from a fabric or polymer mesh and can be fitted with a gel or foam cushion for enhanced comfort and fit. In some embodiments, strap padsare suspended in a taut fashion to support the weight of deviceand to support lateral forces exerted on device. In another example, body framecan comprise a plurality of rigid or semi-rigid padded feet configured to engage the shoulder and abdomen of a patient and to support and spread out the lateral forces exerted on device. In some embodiments, body frameis size adjustable, wherein sections of shaftare telescoping and lockable by way of one or more locks. Body framefurther comprises harnesshaving shoulder and waist straps to secure body frameto a patient (). It should be noted that appropriate sizing and fit of body framesecures deviceto a patient such that framedoes not physically contact the patient, or minimally contacts the patient, ensuring that loads are spread out over the patient's body.

Referring now to, cantilever supportis described in detail. Cantilever supportcomprises first shaftand second shaftsecured to each other by clamps. Similarly to shaft, first shaftand second shaftcan be constructed from any suitably rigid and lightweight material. First shaftcomprises low friction bearingat its upper and lower ends, wherein the upper low friction bearingis slidable along upper railand the lower low friction bearingis slidable along lower rail. In various embodiments, first shaftcan comprise additional low friction bearingsconnectable to and slidable along additional lateral rails on body frame, as described elsewhere herein. Each low friction bearingcan be constructed from any durable material having a low coefficient of friction, such as polytetrafluoroethylene (PTFE) and ultra high molecular weight polyethylene (UHMWPE). Second shaftcomprises headpiece attachmentat its upper end. The positioning of the various components (clamps, low friction bearing, headpiece attachment) are adjustable along their respectively attached first shaftor second shaftby any suitable locking mechanism, such as a ring clamp.

Referring now to, headpieceis described in detail. Headpiececomprises head strapattached to rail guide. Head strapis a flexible piece that is configured to wrap around a patient's head and holds rail guidesecurely to the top of the patient's head. Rail guidehas a lumen sized to fit railand is connected to linkage bar. In some embodiments, rail guidecomprises a low friction bearing within its lumen. Railand linkage barare aligned in parallel and share the same curvature. In some embodiments, the matching curvature can be described as a circular arc having an angle between about 90° and 140°. Railhas a lower end that is attachable to headpiece attachmentof cantilever support. Linkage barcomprises a plurality of holesalong its curvature, each holebeing sized to fit a pin or screw from a lock. Each lockcomprises a low friction bearingthat is slidable along rail. In some embodiments, headpiececomprises at least a first lockhaving a hook attachmentand a second lockhaving a linear gear bar attachment. Hook attachment(shown in greater detail in) provides a point of attachment for a string, wire, or elastic band, and can include a simple hook, a closed loop, or a spring-loaded gate (such as a carabiner design). Linear gear bar attachment(shown in greater detail in) comprises one or more toothed bars to provide a variable point of attachment for a string, wire, or elastic band. Hook attachmentand linear gear bar attachmentare each connectable to a maxillary protraction device. The negative forces exerted on a maxillary protraction device can thereby be tuned by adjusting the position of each lockwith each holealong the curvature of linkage bar. For example, in one embodiment depicted in, hook attachmentcan be positioned between about 30° and 90° relative to a transverse plane, and linear gear bar attachmentcan be positioned between about −35° and 60° relative to a transverse plane.

Combining body frame, cantilever support, and headpiece, protraction deviceis capable of comfortably applying protractionary forces to a patient without loading sensitive head and neck regions while permitting substantial freedom of movement in the patient's head. Locking each component on cantilever supportenables cantilever supportto be laterally slidable on body frameas a single rigid unit by virtue of the slidable connection between its upper low friction bearingto upper railand its lower low friction bearingto lower rail. With respect to headpiece, head strap, rail guide, and each of the lockscan be locked in place relative to each other by way of linkage bar, and the locked assembly is configured to be freely slidable along rail. Devicethereby enables a patient to perform a shaking gesture along the curvature of upper railand lower railin the transverse plane to rotate the head left and right and a nodding gesture along the curvature of railin the median plane between flexion, extension, and hyper-extension of the neck. In some embodiments, headpiece attachmentfurther comprises a rotatable joint to permit a head tilting gesture in the coronal plane (i.e., lateral flexion). In some embodiments, one or more of clampscan include a tension spring, or rotatable joints at headpiece attachmentand rail guidecan permit additional anterior and posterior head movement in the median plane (i.e. a pecking motion).

Referring now to, another protraction deviceis depicted. Protraction deviceemploys similar components as devicethat can be anchored to a bed, gurney, or floor stand. Devicecomprises head braceattached to a curved railby a first lock. Devicecomprises one or more additional locks, wherein each lockis lockable relative to each other to linkage bar. Lockscan each comprise a maxillary device attachmentto support loads for maxillary protraction. Railcan be immobilized by anchorto a headboard, floor stand, wall, or any suitable rigid structure. Railfurther comprises rotating hingeto permit a patient to change sleeping positions while maintaining protractionary forces.

Additional research has identified optional modifications to the innovative cantilevered protraction device described above. A number of improvements have been developed that will enhance the functionality and durability of the device and improve the experience for the user.

The lateral movement of the cantilever support along the body frame may be improved by the use of roller bearings.illustrates a perspective view of a cantilevered protraction device with a roller bearing.illustrates a side view of a cantilevered protraction device with a roller bearing. Roller bearings have a lower coefficient of friction than sliding bearings (such as the slider bearings shown inas elementand inas element), which allows for more fluid motion when moment loads are applied.

illustrates an exploded view of a roller bearing. The roller bearing includes one or more needle bearingssurrounded by an equal number of rollerscoupled to an upper plateand a lower plate. The components of the roller bearing may be coupled together using any suitable types of fasteners, such as screws or bolts. The upper and lower plates may be formed from any rigid, durable material such as metals, plastics or ceramics. Preferably, the upper and lower plates are made of plastic or aluminum. The rollers may be formed from any rigid, durable material such as metals, plastics or ceramics. Preferably, the rollers are made from plastic, aluminum or brass. The roller bearing may optionally include a low-friction substance between the rollers and the upper and lower plates to facilitate the motion of the rollers. The low-friction substance may be any material with a low coefficient of friction. Examples of suitable low-friction substances include polytetrafluoroethylene (PTFE or TEFLON®), ultra high molecular weight polyethylene (UHMWPE), polyimide, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), nylon, polyoxymethylene (POM or acetal), polyesters, acrylonitrile butadiene styrene (ABS), polycarbonate (PC) or polycarbonate/ABS (PC/ABS).

The lateral movement of the cantilever support along the body frame may also be improved by the use of multiple bearings. Preferably, the cantilevered protraction device includes a plurality of bearings on the upper and lower rails of the body frame.illustrates a cantilever support with multiple bearings. The cantilever supportincludes a plurality of upper bearingsand a plurality of lower bearings, which engage with the upper and lower rails of a body frame (not shown), respectively. The upper bearings are coupled together by a first upper bearing plateand a second upper bearing plate. The lower bearings are coupled together by a first lower bearing plateand a second lower bearing plate. The upper bearing plates and the lower bearing plates are coupled to a first shaft, a second shaft, a third shaftand a fourth shaft. The use of multiple bearings helps to distribute the load across a wider distance, which reduces the moment load on each individual bearing. The use of multiple bearings is especially helpful for patients receiving larger protractionary forces for therapy, such as mature patients.

The cantilever support may optionally include additional rolling members to facilitate the lateral movement of the cantilever support along the body frame.illustrates a cantilever support with vertical rollers. Vertical rollersmay be coupled to a bearing platebetween roller bearings. The vertical rollers may be coupled to any of the bearing plates. Additional rolling members may be used to smooth the lateral motion of the cantilever support when exposed to vertical loads.

In addition to securing the multiple bearings, the upper and lower bearing plates shown inimprove the stability of the cantilever protraction device. Using a single plate to couple multiple bearings ensures that the roller bearings stay properly aligned with each other and with the rails of the body frame. In addition, the upper and lower bearing plates ensure that the first shaft and the second shaft maintain a proper vertical alignment. Maintaining vertical alignment of the first shaft and the second shaft is particularly important since these components may impair the lateral movement of the roller bearings if they become misaligned.

The use of multiple bearings allows for various geometries of the bearings and upper and lower plates. The separation angle of the bearings relative to the first shaft and the second shaft may be varied to provide a desired stability and movement profile. A wider separation angle spreads the moment loads and improves bearing performance. However, a wider angle will reduce the range of motion of the user's neck. A pair of roller bearings may have a separation angle of 15-90°. Preferably, a pair of roller bearings has a separation angle of 30-60°. More preferably, a pair of roller bearings has a separation angle of 45° or 60°.illustrates a cantilever support with multiple bearings having a separation angle of 60°.illustrates a cantilever support with multiple bearings having a separation angle of 45°.illustrates a cantilever support with multiple bearings having a separation angle of 30°.

The bearings may optionally be concealed in a housing.illustrates a partial view of a cantilever protraction device with concealed bearings. Concealing the bearings protects the bearings from material that could impact their functioning, such as dirt or food, and prevents objects from being caught in the bearings, such as clothing or a patient's hair.

In an alternative configuration, a rotational hinge may be used to provide lateral movement of the cantilever support about the body frame.illustrates a cantilever support coupled to a rotational hinge, which may be coupled to a body harness (not shown).

The stability of the cantilever protraction device may be increased by including support bars between the first shaft and the second shaft of the cantilever support.illustrates a cantilever support with support bars. A plurality of support barsare coupled to a first shaftand a second shaft. The support bars are located between a first bearingand a second bearing. The support bars offer additional support beyond that provided by the clamps that couple the first shaft to the second shaft (see, element). Alternatively, the clamps may be replaced by support bars. The use of multiple support bars further improves the stability of the cantilever protraction device by reducing the moments applied to the bearings.

The comfort of the cantilever protraction device may be improved by including components that enhance the ability of a user to tilt, nod and rotate his or her head while wearing the device.illustrates a cantilever protraction device coupled to a moveable anchorage. The cantilever protraction device includes a force applicatorcoupled to a headpiece railby a roller bearing. The headpiece rail is coupled to a cantilever supportincluding a shaft. The headpiece rail and the shaft of the cantilever support may be monolithic. The force applicator is coupled to a therapeutic appliance (not shown) by a protraction wire. The protraction wire is coupled to a rotating postby a hinge, which represent the head and neck of a patient. The patient may tilt, nod and rotate his or her head while wearing the device and still receive a constant protractionary force during movement. The rotating post and hinge demonstrate that it is feasible to have the patient move the force applicator and the cantilever support by moving the protraction wire with his or her head.

The force applicator preferably provides a constant force throughout the range of motion when the user tilts, nods or rotates his or her head while wearing the device. A preferred force applicator is a constant-force spring.illustrates a sectioned view of a force applicator including a constant-force spring. The force applicatorincludes a first constant-force springand a second constant-force springwithin a housing. The housing includes a telescoping sleevethat protects the spring when it is extended. The force applicator includes an attachment pointfor coupling the force applicator to a therapeutic appliance (not shown).illustrates a force applicator including a constant-force spring in an extended position. The force applicator preferably includes hard stops (not shown) to prevent overextension of the constant-force spring and exposure of the edges of the spring.

The force applicator may be removably coupled to a mount that is in turn coupled to a protraction device.illustrates a force applicatorand a mountfor coupling the force applicator to a protraction device (not shown). The force applicator may be removably coupled to the mount by a mechanical fastener, such as a screw or spring mechanism, or by non-mechanical means, such as magnets or friction (press fit or snap-fit). The mount includes a roller bearingthat may be coupled to a protraction device (seeand).

Force applicators may provide different amounts of force by varying the width, thickness and/or diameter of the constant-force springs within the force applicator. The force applicator may be configured to provide any suitable therapeutic force. Preferably, the force applicator provides 0.1-10 kg of force.

The force applicator may be coupled to a therapeutic appliance through an adjustable anchorage device.illustrates an adjustable anchorage devicecoupled to a protraction wire. The adjustable anchorage device includes a plurality of holesfor receiving a force applicator (see). The holes may provide a range of angles for the force applicator, such as 0°-45°, including 5°, 10°, 15°, 20°, 25°, 30°, 35° and 40°. The adjustable anchorage device may be removably coupled to the protraction wire by actuating a release mechanism 1330. The adjustable anchorage device may be removably coupled to the protraction wire by a mechanical fastener, such as a screw or spring mechanism, or by non-mechanical means, such as magnets or friction (press fit or snap-fit).

The comfort of the cantilever protraction device may also be improved by customizing the body frame (see). One way to adjust the body frame is by making the strap pads on the body frame removable. For example, the strap pads may be removably coupled to the body frame using fasteners such as snaps, hook and loop fasteners or buckles. The use of removable strap pads allows the fit of the device to be customized to each specific user. For example, strap pads with differing levels of padding or differing levels of flexibility may be selected to provide a desired fit. The strap pads are preferably machine washable. Another way to adjust the body frame is by varying the geometry of the body frame rails. For example, the body frame rails may be straight, angled, curved, or some combination of these geometries. The customization of the body frame will promote a comfortable fit and promote user compliance.